docs: improve writing style of asyncapi document section. Remove redu…

…ndant mermaid diagrams

markdown/docs/concepts/asyncapi-document/index.md

@@ -3,9 +3,9 @@ title: 'Introduction'
 weight: 50
 ---
 
-The AsyncAPI Specification defines a set of fields that can be used in an AsyncAPI document to describe an application’s API. While the document may reference other files for additional details or shared fields, it usually serves as a single, primary document that encapsulates the API description.
+The [AsyncAPI specification](/docs/reference/specification/latest) defines fields for describing an application's API in an *AsyncAPI document*. While the document may reference other files for details or shared fields, it typically serves as a single, primary document that encapsulates the API description.
 
-Furthermore, the AsyncAPI document acts as a communication contract between receivers and senders within an event-driven system. It specifies the payload content necessary for a service to send a message and provides clear guidance to the receiver about the message's properties.
+The AsyncAPI document is a communication contract between senders and receivers within an event-driven system. It specifies the payload content required for a service to send a message and provides the receiver with guidance about the message's properties.
 
 ```yaml
 asyncapi: 3.0.0
@@ -37,5 +37,5 @@ operations:
 ```
 
 <Remember>
-Depending on the implemented protocol (such as MQTT, AMQP, Kafka, etc.), you may have additional fields in your AsyncAPI document. For example, for <a href= "https://github.com/asyncapi/bindings/tree/master/kafka">configuring Kafka bindings</a>.
+Depending on the protocol (such as MQTT, AMQP, Kafka), your AsyncAPI document may have additional fields. For example, for [configuring Kafka bindings](https://github.com/asyncapi/bindings/tree/master/kafka).
 </Remember>